GCW - Partial Extraction Technology

A GCW can also be operated in a way that a certain quantity of water passing through the well shaft is pumped-off or infiltrated into it. Extracting exactly the same amount of water as the upstream into the well, the groundwater downstream from the well is blocked.
Thus, at a remediation site, a complete hydraulic downstream protection of a plume of contaminants with simultaneous exclusive extraction of the injection groundwater can be realised. In addition, there is the possibility to extract water without changing the groundwater level in the well if a certain ratio is maintained.

Numerical Calculation of a GCW with Partial Withdrawal

This has been numerically investigated for unconfined aquifer conditions by Herrling and Stamm (1992). At a distance from the well, the groundwater head at the aquifer surface only slightly deviates from the normal resting position. In low yield aquifers, continuous pumping can be achieved at much higher pumping rate and re-infiltration can be realized for much greater quantity.